Dynamic effects in capillary pressure relationships for two-phase flow in porous media: Experiments and numerical analyses

Well defined experiments and numerical analyses are conducted to determine the importance of dynamic effect in capillary pressure relationships for two-phase flow in porous media. Dynamic and quasi-static capillary pressure-saturation (P -S ) and, ∂S /∂t-t curves are determined. These are then used to determine the dynamic effects, indicated by a dynamic coefficient (τ) in the porous domains which establishes the speed at which flow equilibrium (∂S /∂t = 0) is reached. τ is found to be a nonlinear function of saturation which also depends on the medium permeability. Locally determined τ seems to increase as the distance of the measurement point from the fluid inlet into the domain increases. However, the functional dependence τ-S follows similar trends at different locations within the domain. We argue that saturation weighted average of local τ-S curves can be defined as an effective τ-S curve for the whole domain which follows an exponential trend too.